Abstract: China possesses abundant shale oil resources, holding significant extraction value. Among the technologies applied in shale oil extraction, in-situ conversion technology stands out with unique advantages and represents a crucial direction for future development. Building upon previous laboratory experiments and numerical simulations, this study employs a newly developed multiphase flow numerical simulator. Focusing on representative regions within the well network layout, a geological numerical model is established to finely depict the evolution of each phase and component during the in-situ conversion process. The simulation results indicate that the evolution of each component during in-situ conversion is influenced by factors such as the component's viscosity, the critical temperature of decomposition reactions, and well-to-well interference. Differences in critical temperatures and well interference lead to stratification around heating wells and the formation of enrichment zones. Viscosity affects the production quantity of corresponding components. This study employs a novel numerical simulation method to qualitatively and quantitatively investigate the evolution of components during in-situ conversion of shale oil, aiming to validate the feasibility of in-situ conversion technology and provide guidance for practical production.